Propagation Media
Propagation media is a basic need in which the rooting of cuttings or germination of seeds takes place and also for growing stock plants. Growing media being a store house of water, air and mineral supply ensuring easy germination of seed, rooting of cuttings and their further growth. Proper crop selection of medium is important. The following ideal characteristics are taken into consideration for selection of media.
1. It should be sufficiently firm and dense to hold seeds and cuttings are placed for germination and rooting respectively.
2. Preferably it should not shrink when dry and increase its volume when wet.
3. It should possess sufficiently high moisture retention capacity.
4. It should be porous to drain out excess of water and permit aeration.
5. It should be free from weed seeds and harmful organism.
6. It should be cheap, slightly acidic or neutral.
The various rooting media available soil, Sand, Peat, Sphagnum moss, Vermiculite, Leaf mould, saw dust, shredded bark, Pumice, Perlite, and rice straw, Important ones are given below.
1. Soil:
Light and sandy soils are well suited as rooting or germinating media while loamy silty or clayey soils are unsuitable on account of poor aeration and stickiness. These soils in combination with sand, some organic matter, moss, shredded bark and peat are useful as media.
2. Sand:
Sand consists of small rock grains of 0.05 to 2.0 mm in diameter. Quart sand is most useful as it is suitable for sterilization of fumigation. It has no mineral nutrients.
3. Sphagam Moss:
Commercial sphagnum moss is the dehydrated remains of acid bag plants which is acidic, sterile, light in weight and has high water holding capacity being able to absorb water upto 10 – 20 times of its weight. It contains small amount of minerals. It has ability to inhibit damping of seedlings.
4. Vermiculite:
This is a micaceous mineral which expends markedly when treated chemically. It is a hydrated magnesium diauminium iron silicate. It is light in weight (25 – 45 kg/cu ft.) with good mineral supply and able to absorb fuanity of water i.e. 13.5 to 18 liters / cu ft. Generally particles of 2 – 3 mm are move useful.
5. Leaf Mould:
Leaf mould compost is prepared by putting alternate layers of dried leaves with soil and small quantity of sulphate of ammonia is added to accelerate decomposition rate and to increase mineral content. These layers are watered to maintain decomposition action. For decomposition a period of 12 – 18 months are required.
6. Saw dust / Shredded bark / Wood Sharings:
These materials are the by – products of saw mills. For proper utilization as growing media and decomposition, nitrogen is added in sufficient quantity.
7. Pumice:
This is derived from grey or white volcanic rock consisting of spongy like gaps.
8. Perlite:
This is grey white material is of volcanic origin, mined from lava flows.
9. Pent:
Peat consists of remains of aquatic, marsh, bag or swamp vegetation. Generally preserved under water in a partially decomposed state. Peat moss is broken into pie